Process and apparatus for producing dispersions



Aug. 26, 1930. c,. R. M DONALD PROCESS AND APPARATUS FOR PRODUCING DISPERSIONS Filed July 22, 1927 7 w 5 M22 2/ 2 j Zl/2Z71655" dzxsigned to efliciently Patented Aug-2s,- 1930 UNITED STATES PATE T" orrica I cnnsrrm n. mcnoiuLn, or momma, MICHIGAN, Assmivon TO THE mmrxorn comm, or nosron, MASSACHUSETTS, A CORPORATION or unssacnusn'rrs rnocns's AND nrrAnA'rus ron rnonucme n'rsrnnsron's Application filed July 22 The present invention relates to improvements in a process and apparatus for producing dispersions, and refers more particularto a process and apparatus particularly roduce dispersions of the type described in llnited States Letters Patentto Lester Kirschbraun, Nos. 1,302,810 and 1,615,303. I

In the production of dispersions of the bitumen-pitch type referred to in the afore- ,named patents, it has been found desirable to maintain a bulk supply of material including the end product and to subject said material repeatedly to a rapid agitation in the presence of the dispersing agent to secure exceedingly fine dispersion. In processes and.

apparatus now in use for producing such disperslons means are provided to causeagltation and to permlt circulation-of the mass to and from the zone of agitation. Such means in one type of apparatus commonly used takes the form of an open ended conduit around which the mass is caused to circulate in a container by providing agitating blades ver tically mounted in the conduit-and so pitched as to force. the material to take a circuitous path within the containing vessel and through and around such condui The circulation induced by said agitation a0 while suflicient for most purposes is nevertheless not as thorough and completeas is desirable-inasmuch as only that portionv of the material-whichis in the immediate region of the agitating means is caused to return a number of times to the zone of agitation,

while that portion of the mass which is more remote from the agitating mechanism is returned only a relatively few times to the zone of agitation. Where, for exam Ie', the agitat- 40 .ing means is mounted vertical y within said open ended conduit and the agitating blades are pitched so as to force the material downwardly through said conduit, the circulation I of. themass exteriorly of the conduit is in 45, an upward direction, involving lifting of the mass against its own weight to return it to the up er end of the conduit. Inasmuch as the urden of this lifting action must be borne by the agitating means it is sometimes found that the latter does not set up sufli- 1927. Serial No. 207,620.

cient forces to cause all the material to be recirculated to the zone of agitation the desired number of times.

The present invention is an improvement thereover beingparticularly designed to im- 1 part a positive circulation to the mass undergoing dispersion, thus insuring the return of all portions of the circulatingmass One of the objects of theinvention is to provide a process and apparatus in which the clrculation to and fromthe main zone or zones of agitation is effected by positive means so that-substantially all portions of the mass being dispersed will be positively and forcefully subjected a number of times to the action of the agitating mechanism during the interval between the introduction of the materials into the apparatus and the discharge of the finished product therefrom.

The product producedby the process and apparatus of the present invention is characterized by a high degree of uniformity in the fineness ofthe dispersed particles. An

'advantageof the process and apparatus in which all portions of the materials undergoing dispersion are positively caused to be subjected a great number of times per given time interval to the action of agitating mech anism is that it becomes possible to increase production to amarked extent because the material will be subdivided and dispersed to the desired degree in a much shorter "time.

Other'objects of the invention are to provide an apparatus in' which the agitating mechanism is mounted on a horizontal axis,

permitting direct connections with a motor or other source of power mounted at floor levels; to providean apparatus in which the means for impartinga forced circulation to the mass is disposed ona horizontal axis in a plane difierent than the plane'of rotation of the agitating mechanism; to provide an apparatus in which the agitating mechanism is located at a point where it acts upon only the lowermost portions of the mass of circulating material and while said material is moving in substantially a horizontal plane to provide an apparatus in which the agitating means may move at a relatively higher speed than the means "for imparting positive circulation to the mass, thus inducing accelerated velocity of the mass while passing through the agitating zone. I The invention is characterized by simplicity, certainty in operation and economy in cost. The foregoing and other objects will appear inthe following more detailed description of one embodiment of the present invention, this embodiment being illustrated in the ed at 4. The shaft 3 may be rotated by ashaft 3 may be provided accompanying drawings, in which 1 Fig. 1 is a view taken longitudinally through the apparatus with one wall thereof removed and with certain parts broken away to more clearly disclose the structure.

' Fig. 2 is a view in plan of the apparatus including the illustration of the connections of the various shafts to a power source.

' Fig. 3 is a vertical sectional view taken on line 3-3 of Fig. 1. a

Fig. 4 is a cross sectional view taken longitudinally through the apparatus illustrated inFig. 1 showing a slightly modified form of construction. j

Referring more in detail to the drawings, the numeral 1 indicates as a whole the apparatus which may comprise a container 2 which may be rectangular, circular or oval in shape, and of suitable depth. Disposedwithin the container 2 and spaced a slight distance above the bottom thereof is a shaft 3 extending through'oppositeside walls of the container being journalled in conven-- tional bearings, diagrammatically illustratsuitable source of directly connected t trated in Fi 2). Between the motorb and one of the aring's 4 adjacent thereto the 7 with a gear 6 adapted to. mesh with a larger gear 7 mounted on the countershaft 8, which may be 'ournalled in conventional bearings illustrated diagramower such as a motor 5 matically at 9.

. will be hereinafter more particularly brought out.

Returning now to the shaft 3 intermediate its length, it maybe provided with propeller blades 10, which blades may take any desired shape or' form, the particular pitch depending upon the direction of travel of the material which is subjected to the action of the blade. As illustrating one embodiment of the invention, without intending the illustration to be a limitation, the shaft may beprovided with two sets of blades 11- and 12,

i which sets are'spaced from each other, as

illustrated in Fig. The blac s in the set ereto (particularly illus The purpose of, this shaft 8.

11, it is to be noted, are so pitched as to propel the material subjected to the action thereof in a clockwise direction while the blades of the set 12 may be so pitched as to impart a movement to the material being subjected to the action thereof in a counter clockwise direc-' tion, the purpose of which will be hereinafter more particularly brought out. i

Returning now to the shaft 8, intermediate its length it may be provided with bevel'gears 13 and 14 adapted to mesh, respectively, with bevel gears 13 and 14' mounted respectively on shafts 13" and 14". To the shafts 13" and 14" are respectively keyed rotatable elements 13 and 13", which in one embodiment of the invention may take a shape resembling that of a spool having its end faces 15 en- 'larged. The drums 13 and 13 may be substantially identical in shape, and the shafts 13", and. 14 are preferably mounted in spaced parallel relation, nalled through the front the container.

being suitably jourand rear walls of It is to be noted, that each of the elements ter of thehub portion is preferably about diameter of the the curvature of the body porone-third to one-fourth the discs 15,-and

tion thereof is such that they join the inner surfaces of the ends 15 inwardly of the peripheral ed e of said discs. Thus there is provided he ow each of the elements '13 and 13" an enlarged space 16'for a purpose hereinafter to be set forth .The shafts 13' and 14 are preferably spaced apart a distance somewhat greater than the end faces15 so as to-afford necessary clearance between the'peripheral edges of adjacent ends.' r-

The enlarged spaces 16 referred to above may be saidto constitute the agitating zones ofthe present dispersing apparatus. The agitating mechanism comprising ler blades it Being propeller blades is such that they will clear 10 is disposed within these zones,

the propelunderstood-that the radius of the:

the inner surfaces of the-ends 15. I haveshown in each of the sets 11 and 12 three propeller blades. It is'to be understood, of course, that one or} more may be used and that the number in one agitating zone relative to another may differ. I

As a feature of the present invention due to reduction in gearing designated diagrammatically at 6 and 7 and due to the position andsize of the bevel gears 13' and 14, the

drama 13' and 13" will be caused "to rotate inopposite directions, forinstance, as ind1 cated by the arrows in Fig. 1 and at. speeds materially lower than e speed of rotation .of the propellers 10, the ar rangeinent as itself be jacketed for low in an obvious manner, I medium being preferably led shown being such that the drum 13frotates in a clockwise direction while drum 13 rotates counter clockwise and at a lower number of R. P. M. than the number of R. P. M. of drum 13. Thus, for example, where the propellers 10 rotate at a speed of 1,000 B. P. M. the drum 13 may be driven at about 30 R. P. M. and the drum 13*- at about 20 R. P. M. I

While it is preferable in certain instances to so gear the respective shafts that the drum 13 will rotate in a direction opposite to the direction of rotation of the drums 13 dispersion may be also effectively carried on with rotation of both drums in the same, rather than in opposite directions and at substantially equal speeds.

Feed pipes for introducing into the apparatus the base to be dispersed and the dispersing agent are illustrated respectively at 17 and 18.

In order to maintain a regulated temperature on the contents of theapparatus during the dispersing action, and in order to control the temperature, the drums 13 and 13 may be hollow, if desired, or they may be jacketed in an obvious manner for the reception of the temperature regulating medium which may comprise, for instance, water. In either event it is preferable that the temperature regulating medium be conducted into the interior of the drum or drum jacket and out again by making the shafts 13' and 14' holin at one end of said shafts and withdrawn out of the opposite end thereof.

In certain instances the container 2 may the purpose of temperature regulation.

The finished dispersion may be withdrawn through the outlet pipe 19 controlled by the gate or valve20. The outlet pipe 19 may be positioned in the base or in the side wall of the container. the exact position being dependent upon the determination of the most efficient point for withdrawal.

, In the modified type of construction illustrated in Fig. 4, there is provided means for facilitating the positive circulation of the mass being dispersed by the elimination of any dead spaces, which means may comprise the trough-like elements 21 arranged substantially parallel to each other and extending transversely of the container, which may be separate or integral with the container. These trough-like elements 21 are separated from each other by the intermediate upwardly extending curved portion 22. The surfaces of the hub portions 13 and 13 are preferably concentric with the troughs 21 to provide a curved surface facilitating directional flow of the circulating mass. The upwardly extending portion 22 as well as the upwardly extending portions 23 may be prothe regulating the materials 3 may extend. The construction of the container shown in Fig. 4 is generally similar to the container shown in Fig. 1 with the addition of the directional troughs. The withdrawal pipe 19 in Fig. 4 is illustrated as being connected to the side wall of the container. v

The operation of the apparatus will be apparent to one skilled in the art. The materials being introduced at 17 and 18 are caused to circulate in planes generally vertical by means of the slowly revolving drums 13 and 13", and these newly introduced materials as well as portions of the mass already within the container are forcefully and continuously directed to the agitating zones 16 Where the rapidly rotating propellers 1O subject the materials to a severe agitating to flow in substantially a horizontal direction longitudinally of the container, and the material thus force-d away from the region of the propellers is conveyed in substantially a circular path about the drums and back to the agitating zones. Depending upon the direction of rotation of the drums and the relative speeds at which the latter revolves, more or less of the material which has been subjected to the agitation of one of the sets of propellers will become intermingled with portions of the material which has undergone agitation by having the action of the other set and the intermingled masses will be again circulated by the revolving drums and returned to the agitating zones.v Thus, it will be apparent that undergoing dispersion will be brought positively and repeatedly into the sphere of influence of the agitating mechanism in the interval between introduction of .the materials into the apparatus and the discharge of the finished product therefrom.

By controlling the introduction of the base to be dispersed and the dispersing agent, as well as the discharge through the outlet 34, the apparatus of the present invention may be utilized either in a batch type of operation or in a semi-continuous or continuous operation, as will be readily understood by those ,skilled in this art.

The finished dispersion as generally produced is of sufficiently low viscosity to permit discharge in a continuous stream through the outlet 19 upon the opening of the valve. 20, particularly where the outlet is located in the base of the container 2. In some instances, however, depending upon the character of the-starting material, the finished dispersion may be in the form of a thick heavy paste,

resisting to a certain extent spontaneous flow of blades 11. and 12 within the so-called agitating zones, it is to be particularly understood that a larger number of drums or sets of propellers, or both, may be mounted within a single container in carrying out the-prin ciples of the present invention. Furthermore, if desired, a number of units such as described may be arranged in parallel as a battery within a single container, or they may .be mounted in separate containers and connected in series so that the end product of one unit of the series constitutes one of the starting materials for one of the succeeding units of the series. This would be particularly desirable where one drum or a unit of two drums rotating, for instance, in opposite directions was utilized as a means forsubjecting the mass to a beating action for the purpose of reducing. its viscosity, thus permitting the introduction and incorporation of y increased quantities of base in a succeeding drum or unit of two or more drums.

Moreover, while the apparatus of the present invention has been described as particularly well suited for the production of dis- .persions of bitumen-pitch bases, it should be understood that other analogous procedures or functions may be performed therewith.

Thus, it is conceivable that the structure may serve very well (with slight modifications, if necessary) as a mere agitator or mixer for materials in either solid or liquid state, or as a stirring device for promoting solution, or other union of one material with another.

It is to be understood, of course, that the connections between the side walls and base of the container shown in Fi 1 may be rounded instead of taking the form of a right angled connection, as shown, to produce in effect the result of using the elements 21 shown in Fig. 4.

I claim as my invention:

1. An apparatus of the character described comprising, in combination, a container, ro tatable means mounted on a horizontal axis for causing rapid agitation oi material with- -in said container, and non-agitating means comprising an element also mounted for retation on a horizontal axis at an angle to the first mentioned agitating means for forcibly and positively directing material into the sphere of influence of said firstnamed agitating means.

2. An apparatus of the character described comprising, in combination, a container,

means for causing rapid agitation of material within said container comprisin elements mounted on a rotatable shaft, an nonagitating revoluble .means comprising elements mounted on a shaft rotating at substantially right angles to the first mentioned shaft for forcibly and positively directing material into the sphere of influence of the first named agitating means.

3. An apparatus of the character described comprising, in combination, agitating means within said container adapted to rotate at relatively high axial speed, and non-agitating revoluble means for positively forcing material within said container into the sphere of influence of said agitating means, said revoluble means being adapted to rotate at an axial speed substantially less than that of the agitating means.

4. An apparatus of the character described comprising, in combination, a container provided with a valved outlet, means disposed in said container for subjecting material to a rapid agitation while passing in a substantially horizontal plane, means for imparting circulation of said material to. and from said agitating means, comprising spool shaped drums mounted for rotation on a horizontal axis at an angle to the plane in avhich the agitating means rotates.

5. An apparatus of the character described comprising, in combination, a container, spool shaped drums adapted to rotate in opposite directions and circulate material upwardly and downwardly within said container, said drums having reduced hub portions providing enlarged spaces, and agitating mechanism arranged within said spaces adapted to cause rapid agitation of the circulating material.

,6. An apparatus of the ('llttItW-l-(H' described comprising, in combination, agitating means rotatable on a horizontal axis within the container, and non-agitating means rotatable on an axis extending at an angle to the axis of the agitating means for positively forcing material within'the container to the sphere of influence of the agitating means.

7. A continuous process for dispersing a waterproof substance in water, which com prises maintaining a bulk supply of material comprising dispersed end product, causing portions of said bulk supply to be positively carried in mass form up and down in two opposed cyclically circulating paths, introducing to said paths fresh charges of materials to be dispersed, and during said continuous cyclic circulation subjecting said mass to rapid agitation and accelerated velocity to produce attenl'iationand dispersion while it is moving in a substantially horizontal plane during the lowest part of its cycle.

8. A continuous process for dispersing a waterproofing substance irewater, which comprises maintaining a'bulk supply of material comprising dispersed end product, causing ortions of said bulk supply of material to e mechanically carried in mass form up and down in two opposed cyclically circulating paths, introducing to said paths fresh charges of materials to be dispersed and during such continuous cyclic circulation subjecting said -mass to rapid agitation and accelerated veloc- 

